Recent research advances have led to the development of fuel cell devices which utilize bacteria as catalysts to create useful products, such as electricity and hydrogen. The bacteria oxidize a substrate, electrons produced are transferred to an anode and flow to a cathode through a conductive connection which may be further connected to a load, such as a device powered by electricity produced by the fuel cell.
While development of these devices holds great promise for progress towards new energy technologies, certain applications are limited by an inability to provide a bacterial oxidation substrate in required amounts in order to keep the fuel cell operating at a desired level.
For example, sediment microbial fuel cells are desirably operated remotely but are hampered by relatively low power output. A sediment microbial fuel cell generally includes an anode embedded in an anaerobic marine sediment, and a cathode suspended in the overlying oxygenated seawater. The electrons released by the bacterial degradation of the organic matter in the sediment flow from the anode to the cathode through an external circuit, while protons diffuse through the water between the electrodes. The electrons and protons then react at the cathode with oxygen, forming water. However, sediments are generally relatively poor in organic matter content, ranging from about 2-6%, such that power output is limited.
Thus, there is a continuing need for substrate formulations for microbial fuel cells and microbial fuel cell configurations for use with substrate formulations.